Direct photo-patternable,low-temperature processable polyimide gate insulator for pentacene thin-film transistors

We have developed photo-sensitive, low-temperature processable, soluble polyimide (PSPI) gate insulator with excellent resistance to the photo-patterning process. The PSPI was synthesized through one-step condensation polymerization of monomers 5-(2,5-dioxytetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (DOCDA) and 3,5-diaminobenzyl cinnamate (DABC). PSPI thin film, fabricated at 160 °C, has a dielectric constant of 3.3 at 10 kHz, and leakage current density of <1.7 × 10^?10 A/cm², while biased from 0 to 100 V. PSPI could be easily patterned by selective UV-light exposure and dipping into γ-butyrolactone. To investigate the potential of the polyimide as the photo-patternable gate insulator, we fabricated pentacene OTFTs and confirmed the PSPI’s resistance to the photo-patterning process. The photo-patternable polyimide shows promise as gate dielectrics for OTFTs.